Recently, demand for cameras (stereoscopic imaging apparatuses) that may shoot 3D (stereoscopic) images has been getting stronger. As an imaging method of stereoscopic images, a beam splitter method (half mirror method) of shooting using a half mirror, a side-by-side method (side-by-side twin-eye method) of shooting using two imaging apparatuses placed physically side by side, etc. are known. In these shooting methods, the imaging apparatuses are mounted on a pedestal called Rig for shooting, and the degree of freedom in mounting of the imaging apparatus is higher. For example, the distance between lenses of two lenses for shooting of stereoscopic images (base line length; hereinafter, referred to as IAD: InterAxial Distance), convergence, angle of view, etc. may be selected with the high degree of freedom.
However, while the degree of freedom is high, there is a problem that lots of efforts and time are necessary for setting and adjustment with respect to each shooting because the apparatuses are mounted on the rig. Further, there is a problem that the rig for the beam splitter method is significantly large-scaled and not suitable for use of shooting in the fields and interviews.
To solve the problems, two 2D video shooting cameras for shooting by the side-by-side method are incorporated in one housing to form an integrated two-eye 3D camera. The integrated two-eye 3D camera having the configuration does not need assembly or adjustment of alignment. Further, the camera is compact and easy to carry at shooting in the fields and interviews and has an advantage to promptly start shooting after setup in a short time.
However, the integrated two-eye 3D camera is basically according to the side-by-side method, and adjustment of IAD is limited. That is, the respective optical systems and imagers of the two eyes physically interfere with each other, and IAD is difficult to be made shorter than a certain distance determined depending on the placement positions of the optical systems and imagers. Accordingly, for example, in the case where shooting is performed very close to a subject, parallax when the subject is displayed on a 3D display several meters behind it exceeds the range of parallax when a human can comfortably view 3D images.
As the cases where the subject and the imaging apparatus is very close, for example, shooting of an interview of a person, shooting at the backyard in sports broadcasting, etc. are conceivable. In the cases, the distance between the subject and the imaging apparatus is about 1 to 2 m and the convergence point is set to the distance of 1 to 2 m. In the cases, the most useful IAD for bringing the parallax within the range in which a human can comfortably view 3D images is considered to be 10 mm to 40 mm. However, in the current two-eye 3D camera, it is difficult to realize the short IAD while keeping image quality and functions, i.e., without reducing the diameters of lenses or sizes of the imagers.
In the case where shooting is performed according to the above described beam splitter method, two imaging apparatuses do not physically interfere with each other and the IAD can be made very short. However, as described above, there is the problem that lots of efforts and time are necessary for setting and adjustment with respect to each shooting, and the problem that the method is not suitable for shooting of an interview of a person or shooting at the backyard in sports broadcasting still remains.
For example, in Patent Document 1 (JP-A-2003-5313) a stereoscopic image shooting apparatus in which the convergence point can be adjusted to an arbitrary position with the focus point of the camera coinciding with the convergence point of two eyes is described. Using the apparatus, shooting can be performed with the IAD equal to the pupil distance of a human and, in the case of close-in shooting, videos with natural stereoscopic effects may be shot.